Bob Thrun, prussiking at an early 1980's Old Timers Reunion at Bowden, WV.

Bob Thrun died unexpectedly at his home in Indian Head, Maryland, on February 7th, 2017. He had been feeling ill with the flu, and after he failed to check in with his sister in California, she contacted the police, who found him passed away in his bed, having died in his sleep.

Bob was a longtime caver who joined the NSS, the D.C. Grotto, and the Potomac Speleological Club (PSC) in 1966. His caving interests included cave surveying, vertical caving, photography, and attending the full range of Virginia Region (VAR) social events, Old Timers Reunions, and NSS Conventions, which he rarely missed.

Bob was an analytically brilliant man. He wrote the CMAP (FORTRAN) computer program, one of the first computer programs to process cave survey data for extremely large caves using simultaneous loop closure to handle survey errors. His program, which was used in both the Friars Hole and Organ Cave Systems, allowed the project leaders to standardize their data, locate errors, and anticipate connections. It was a very powerful program, and it may have been the first such developed in this country.

Bob also helped define and publicize the use of standard cave map symbols. His pioneering work with loop-closure techniques had significant influence on several later survey programs, including SMAPS, WALLS, and others, and these techniques are standard accepted practice today. He was a major and frequent contributor to the NSS Survey Section’s Compass and Tape.

Over his caving career, Bob was involved with many major VAR survey projects including Hellhole, Simmons-Mingo Cave and the Elk River System, Friars Hole, and many others. He was a wealth of information on West Virginia’s caves, and was particularly knowledgeable regarding the caves on the Elk River and in Germany Valley. He also had “sticky fingers,” in that he stored and archived cave data that he had not produced, such as the underwater surveys of Judy Springs, in Germany Valley. And, although his contributions had slowed significantly in recent years, Bob was still a member and contributor to the Germany Valley Karst Survey.

Bob initiated the modern Hellhole survey project in 1970 when he led a survey team into the newly discovered “New Section,” which includes the Shipp Room. He was the “tech guy” managing the survey data, but because he was more of an innovator than a coordinator, this project would remain a very loosely organized, PSC-affiliated project until the opening of the Flood Section in 1986. After that time, expanding caver interest, quarry politics and bat conservation issues demanded a more rigorous management, which was not Bob's interest; hence others took over control of the data and the project.

Of major importance to Bob was his involvement in a month-long 1967 caving expedition to the mountaintops of Guatemala that was coordinated by Stan Carts and PSC. The expedition faced many obstacles, including remoteness, poor roads, altitude, and difficulty getting food and, unfortunately, found only a few caves.

As a survey sketcher, Bob was a perfectionist. It was a standing joke that if someone kicked a rock in a cave he was mapping, he would have to update the sketch of that section. Although Bob was a major participant in many Virginia and West Virginia survey projects, his perfectionist tendencies meant he published only a few maps, such as Atkins Cave, in Monroe County, and Alpena Cave # 1, in Randolph County. Many of his maps were awaiting “one more survey trip,” but were ultimately superseded by other cartographers with perhaps less patience and lower standards.

In 1971, Bob wrote one of the first books on vertical caving techniques, titled Prusiking, and he worked for many years to perfect vertical equipment and techniques. He was one of the first cavers to drop Fantastic Pit in Ellison's Cave, Georgia, and he had a significant, extensive collection of historic vertical caving equipment. For many years, Bob would sew his own vertical rigs using an industrial sewing machine that he had acquired.

Bob had a large library of caving books and newsletters. To the casual visitor the collection looked like chaos (and was actually stored in two separate apartments for several years), but Bob was always able to quickly retrieve documents when anyone asked for them.

Bob was an avid photographer of VAR caving events and NSS Conventions, where he could always be found with a camera around his neck, quietly observing and taking photos. He was one of the last photographers to surrender to digital photography. His collection remains an important photo archive from the period of the late 1960s to the current time.

Bob is survived by a sister and a brother who have very generously given his library, vertical gear collection, and photographs to Gary Storrick to be conserved within the caving community. Gary plans to merge Bob's collection of vertical gear with his own extensive collection and then provide the duplicates to the NSS Museum. The same will be done with Bob's books. The NSS plans to scan his slides and make the digital files available for appropriate use by the caving community.

Bob was approved as a Fellow of the NSS, but declined to accept the award. This was typical of his low-key lifestyle his desire to stay out of the limelight, and to avoid receiving awards when he felt there might be others that were more deserving. It is notable that he successfully avoided getting sucked into speleopolitics.

Bob was a long-time Maryland resident. During his career, he was a U.S. Navy civilian physicist with expertise in the analysis, modeling, and effects of underwater explosions due to naval weapons. He started his career in the mid-1960s at the Naval Ordnance Laboratory at White Oak, Maryland, and retired more than 40 years later from the Naval Surface Warfare Center Indian Head Division, at Indian Head, Maryland. His job expertise was occasionally applied to developing innovative new technologies for cave exploration and survey. Some of the attempts were successful and some not so much, but there were no serious injuries!

The caving community seems to attract unusual personalities. Bob Thrun certainly fit this pattern, but it made him an outstanding caver who was well liked despite (or because of) his eccentricities. His death leaves a void in our tribe that will be hard to fill.

Gary, on behalf of rope geeks everywhere, I'd like to say THANK YOU for saving Bob's extensive caving archives, photos, books, and vertical gear. Bob published many articles over the years, but much of his legacy to caving could have ended up in a landfill without your help.

From some old notes, I see that my association with Bob Thrunbegan a decade & a half ago (2002-05) when he sent a query viae-mail regarding knots, and then soon followed up with a phone call.Well met, we chatted for over an hour, and a relationship was born.We met in person only once, and too briefly, at a 2003 IGKT conferencein Newport-News at the Mariners Museum, where I hurried us back overthe library for a look at some of their old knots books, and esp. at theprivate work (of many volumes) by Henry Grant North Bushby (ca. 1902ff).

He was a good source regarding the (rather shabby) knotting literature,and joining forces at one point we were able to find prior sources toabout 2/3 of the knots in the Richard Hopkins Knots (Pocket Guide)which had proudly promised "... over 100 knots, each illustrated withspecially commissioned illustrations". One is left to infer that thespecial commission paid for a scanner and other books. (I have little doubtthat all are plagiarized, but that is a matter awaiting further pursuit.)

So, it was quite a shock and sad news to receive the e-msg. from hissister about his passing, seeking contact info for the guy with all thedevices (viz., Gary), and an offer to save Bob's knotting library. I have nowarrayed the few crates of books and measured 4'9" and 101 or so (someduplicates). AND some cordage samples Bob had, which inevitably hasled me to much fiddling, and much sketching --something I'd recentlypushed myself to do so as to liberate my own "play ropes" from beingthe sole record of some *new knot*. (Counting sketches just dating"2017", I'm over 75.)

And I can see that for a long time, I will be having --in a way--"conversations with Bob".